Focusing means for incandescent studio spotlights



June 8, 1937. J. c. ROSE 2,083,506

FOCU SING MEANS FOR INCANDESGENT STUDIO SPOTLIGHTS Filed May 21, 1935 3Sheets-Sheet 1 Dluerzfar .52; 6. Base.

June 8, 1937. J. c. ROSE 2,083,506

FOCUSING' MEANS FOR INCANDESCENT STUDIO SPOTLIGHTS Filed May 21, 1955 5Sheets-Sheet 2 l I I I I I I I I I I I I I I I I I I I I I I I I l I l lI I I I I I I l I J l I I I I l Invenlur cfess'afiase.

a /6 I a l2 /4 m J. c. ROSE ,08

V FOCUSING MEANS FOR. INCANDESCENT STUDIO SPOTLIGHTS June 8, 1937 FiledMay 21, 1935 5 Sheets-Sheet 3 Inventor- Jss 6. Rose.

Z54 I /Z llZ flllorrzey Patented June 8, 1937 ssssum FOCUSING MEANS FORINC'ANDESCENT STUDIO SPOTLIGHTS Jess 0. Rose, Los Angeles, Calif.,assignor to Motion Picture Electric Products, Los Angeles,

Calif., a corporation Application May 21,

15 Claims.

This invention relates generally to incandescent spot lamps such as areused in motion picture studios for illumination of sets, and moreparticularly to focusing means for the incandescent light globe of suchlamps.

Studio spot lamps of the character mentioned are ordinarily providedwith a light globe that is movable forwardly and rearwardly along theaxis of the reflector for the purpose of adjusting the lamp to cast arelatively small spot of light, or else to spread the light out andflood the object. The spot is of course formed when the globe is at ornear the focal'point of the reflector, and flood characteristics areobtained when the globe is moved nearer the reflector. It has been thepractice to provide an operating means for adjusting the position of theglobe between spot and flood positions involving a lead screw havingscrewthreaded connection with globe carrier member. Such lead screw isordinarily rotated by a crank or similar. means, and a large number ofcrank rotations are required to move the globe between spot and floodpositions. Obviously, adjustment of such a lamp involves considerableef- 5 fort and consumption of time. The time factor involved inadjusting such lamps is of particular importance in the lighting of amotion picture set, since time is at av high premium, and when thetaking of a scene is Waiting, a motion picture director is highlyimpatient with the slightest delay in making final lamp adjustments.

It is accordingly one object of the present invention to provide aquickly operating and generally improved means for adjusting the globeof an incandescent studio spotlight between spot and flood positions.

In accordance with a preferred form of the present invention, the lightglobe carriage is arranged to slide on a pair of guide rods which areparallel to the axis of the reflector, and the carriage is moved througha link connected at one end to the carriage and at the other end to anarm mounted on a manually rotatable shaft journalled in a wall of thelamp. The arrangement is made such that the full range of movement ofthe lamp globe carriage (between spot and flood positions) isaccomplished by one revolution or less of the manual operating shaft,that is, within one revolution of said shaft, full adjustment being hadin'present preferred forms of the invention by a 180 degree turn of saidshaft. A suitable knob or handle is mounted on the manually operable endof the shaft, and the shaft carries a suitable pointer, with which isassociated a scale 55 showing spot, flood, and intermediate positions.

of California 1935, Serial No. 22,546

Since in such an arrangement as thus. generally described, the lightglobe carriage moves rather freely on its guide rods, the manualadjustment means as described offering no particular resistance, thelight globe carriage has a tendency to slide along the guide rods as thespot lamp is tilted up or down on its horizontal trunnion mounting axis.It is a feature of the present invention that such accidental movementor displacement of the light globe carriage in the course of ordinaryoperation is prevented. This is accomplished, in a preferred embodiment,by the provision of friction means which yieldingly resists adjustmentmovement of the light globe carriage on the guide rods. This frictionmeans offers the necessary resistance to prevent accidental displacementof the carriage, 'but does not bind the operating means sufficiently tointerfere with desirable ease of operation.

It is customary to transport lamps 'of the character mentioned piled oneon top of another,.with the front faces of the lamps turned downwardly.The front lenses of the lamps are for thispurpose removed, and thecrowned back of each lamp projects somewhat within the front opening ofthe lamp next above it. The lamp being "in such a position, the lightglobe carriage tends to work downwardly on'its guide rods as'the lampsare transported, even despite the frictional means provided to preventmovement in ordinary operation. As thelight globe carriage thus worksdownwardly, either the spill-ring carried by the carriage immediately infront of the globe, or

the globe itself, is apt finally to engage the v crowned back of thelamp next below. I If a spill- 1 ring is on the carriage, it isthereupon caused to be bent back, with the frequent result of comingagainst and breaking the globe, while if no spill-ring is in place, theglobe may become broken by direct engagement with the crowned back ofthe lamp below. It is accordingly a further object of the invention toprovide a lamp that has a comparatively freely moving light globecarriage, with a locking arrangement preventing the light globe carriagefrom accidentally moving forwardly from a fixed retracted position whenthe lamp is in a facedown position.

The invention will now be best understood ,by referring to the followingdetailed description of typical and preferred embodiments thereof,reference for this purpose being had to the accompanying drawings, inwhich: i

Fig. 1 is a front elevation of a'lamp embodying my invention, the frontlens being removed and parts being shown in section;

Fig. 2 is; aev ertical section taken on line 2'-2 01 Fig; Lwi W ertainparts shown in elevation; Fig.2iris' a detail section taken on line2a-2a, of Fig. 2;

Fig. 3 is a view similar to'a portion of Fig. 1,

but showing thelamp carriage in a different position;'

Fig. 3a is a, section as indicated by line 3a--3a 01 Fig. 3;

Fig. 3b is a detailsection taken as indicated by line Ob-Sb of Fig. 3a.;1'

Fig. 4 is a detail sectiontaken as indicated by line 44 of Flg. 3;

Fig. 5 is a detail taken as indicated byarrows 5- -5 in Fig- 1;

Fig. 6 is a view similar to Fig. 4' but showing a modification;

Fig. 7 isa view similar to a portion of Fig. 3

but showing. a modification of the lamp carriage operating means; and

Fig. 8 is a viewof the back of the lamp, with the crowned back closuremember broken away. I

The lamp,designated generally by numeral i0; is made-up of front andrear ring frame members' H and'l2, respectively, formed with inwardlyextending flanges l3 and H (see Figs. 1 and 2).

Mountedwithin flanges l3 and are two substantially semi-cylindric shellor side wall 'meme bers l6. The lower edges of these side wall membersdefine an opening which communicates with the interior'of a rectangularcas'e orboxylflil iigs. l and 3a). Ring flange members l3 and I4terminate. at edges H, as indicated, inuFig. 311.

Box ll,.isiprovided' with brackets l8a:which engage the 'undersides .ofthe lower ends of flanges II and. I14, and screws 'l9-passing-downwardly through side walls i6 andqflanges I3 and i4 threadedintobrackets 18w hold the parts in assembly, all as illustrated :inFigs. 3a: and 3b. Thiscasing member I8.is, designed to house certainoperating mechanisms for the carriage;

etc.;;%and mayi'or the purpose of certain-of the claims be consideredas;a part of the lamp frame. -Rearward gring Irame I2 has an opening 22adapted to receive a-rear, annular-closure member 23 carrying va usualcurved reflector mirror ,24. Thebackof'the reflector is yieldinglysupported by an arrangementof four coil springs 24:; covered. with asuitable padding material, as jasbestos,'as indicated at 24b,.thejunctures of the severalsprings being connected bymeansof supportingwires,Mo to,annularflmember 23. 7 The lamp has a crownedback member 23a,which is securedto member 2 3, asshown l ont; frame ring [I has an}annular. opening 25, which :receiyes a carriage ,ringj26 in which ismounted. firont..glass' orf lens" member .21. v The .is trunnioned onehorizontalfaxis at 28 and 29 on the upper ends of supporting arms 32mounted on a usual standard 33.

Theincandescentlamp globe is designated at 3i l,. and is shown mountedon a, lamp globe carriagef 3 l which'is adapted to slide forwardly andrearwardly,,.in a direction parallel to the axis of mirror 24,;ona pairof parallel guide rods 34 and 35 which are mounted at their ends 1111brackets 36 formed on the inner surfaces of the ends of box ll. Asclearlyshown,theserods are parallel to the axis of mirror "Hand are-fina horizontal plane. Carriage 3i fis'providecl with'a bea'ring 31'whichslides freely on guide rod 35, and with forward and rearward bearingsand 39 which slide freely on' guide rod 34.

, Carriage 3| is shown provided with a forwardly extending bracket 40 onwhjchis mounted the supporting arm 4| of a conventional spill-ring? 42,which is positioned immediately in front of "light globe, 30. As a meansfor detachablymounting arm M on bracket 4!), arm 4| is provided with anopen-ended slot which is adapted to receive a clamp screw fr'nounted :inbracket 40, a wing nut 45 being provided on screw 44 .to

bear against the side of armll and thus clamp it tightly to bracket 40.It will be evident that this, construction permits the spill-ring to beeasily and quickly mounted and dismounted.

The preferred'means in accordance with the H present invention forsliding lamp carriage 3i back'andforth on rods .34 and 35,'for thepurpose of adjusting the lamp globe between flood and spot positions,will now be described. A horizontal operatingshaftifl is rotatablymounted inside wall 5| of box l8 (Figs. 2 and 4). This shaftis solocated as to betothe rear of forward lamp-carriage bearing 38 when thelamp-car riage is in its rearward or flood position, as itis in. Fig. 2,and is located just below guide rods 34v and 35, as shown. Pinned on theinner end of shaft 50 is an arm-"52, the swinging end of. which ispivotallyconnected to oneiend of a link 53, the' other. end of link 53being pivotally'connected at 54 with lamp-carriage bearing. "The outerend of shaftg50 is provided with an operatingknob 5'! provided with ahandle 58 and a pointer 59, the latter -moving over scale Gilformedon ascale plate 6| :which is afllxed, as

by screws :62, to thepoutersurtace of wall 5|;

It willbe evident from a consideration of Figs;

2 and 3 that the-full range'of forward-and rear ward movement of thelamp carriage is accom plished by a 180 degree rotation oi shaft 50*andarm 52.' The lamp carriage is in} its" rearmost (flood-light) positionwhen arm 52 is in ahori zontal rearwardlyextended position, and is initsextreme 'forward position' -(spot) whena'rm L52 globe 30beingsubstantially iat'thefocafpoint oi mirror 24 11 the latter position. Therange of movement ofthe lamp carriage is of course deetermined by thelength of amfsz, aiiid iink safis' 'is in a horizontal forwardlyextending position,

of suchlength as will place the carriage and lamp in correctffulbfioodand spot, positions'in the two described positions of arm 52. Pointer 59is so mounted on shaft 'as'to point straightthe carriage is illustrated.in aposition. close to ,spot, and in Fig. 5 the pointer is shownin a.corresponding position,

In the .positionof Fig. ;2, arm 52 is just above horizontal position andis in engagementwith guide rod .34, which overliesl arm '52 and pro:vides a stop-therefor (see Fig; 2a).. When arm-52 isithus in engagementwith guide rod 34, pointer v 52'fis above"flood position, and itsposition is designated on scale .60. by the wordxlock. It will be'evident that inthis position of the device, the lampc arri'a'geis-mov'ed slightly forward from its 'xtreme'rearward position, but thatfur-. 'ther'forward movement is prevented by the en'- gagement of arm"52 w'ith'the underside of guide rod 34. The advantage of this lockposition will be explained hereinafter.

A friction means is provided to establish a desirable resistance tomovement of the lamp carriage on the guide rods, so that the carriagewill move easily when handle 58 is turned, but will not slide back andforth as the lamp is tilted up or down. As shown in Fig. 4, operatingshaft-50 is provided just inside of wall with a friction disk 10, saiddisk in the present instance being provided with a hub 1| fastened toshaft 50 by means of pin 122. Disk comes against one side of astationary friction disk 14 carried by the outer ends of theaforementioned screws 62, disk 14 being positioned between sleeves 15bearing against wall 5|, and nuts 16 being screwthreaded on .the rearends of the screws. Mounted on shaft so as to bear against the surfaceof disk 14 which is opposite disk10, is a friction disk 18, said disk 18being provided with a hub 19 which is arranged to slide longitudinallyon shaft 50 but is held against rotation thereon. For instance, hub 19may be formed with a slot formed in a direction parallel to shaft 50,which slot receives a pin 8| set into said shaft. Friction disk 18 isthus splined on shaft 50. Encircling shaft 50 and bearing against theend of hub-19 is a compression spring 83, the other end of which seatsagainst a collar 84 tightly mounted on shaft 50, all as clearly showninFig. 4. It will be evident that spring 83 presses friction disk 18 intotight engagement with one surface of stationary friction disk 14, andalso acts through collar 84 and shaft 50 to press disk 10 into tightengagement with the other surface of disk 14, thus setting up ayieldable or frictional resistance to rotation of shaft 50. Theadjustment of spring 83 is of course such, however, that shaft 50 may beturned without difficulty, only sufficient frictional resistance beingset up to prevent carriage 3| from sliding back and forth on the guiderods -merely due to tilting of the lamp.

It will now be evident that I have provideda novel lamp carriageadjustment mechanism which is quick in action, simple in construction,and convenient in use. The operating handle, in thepreferred form of thelamp, is rotated through but one half of a turn to translate the lampcarriage over its entire range of movement. 'The mechanism moves easily,but is prevented from accidental displacement from a given position asthe lamp is tilted, by the yielding friction means acting on the manualoperating shaft.

When lamps of the type disclosed are to be transported, they arecommonly stacked one on top of another, with their crowned backs up, andthe front lens carrying rings removed, so that the crowned back of eachlamp may be received within the open side of the lamp above it. When thelamps are so stacked, the operating handle is turned to lock position,which places the lamp carriage in the position of Fig. 2. In suchposition, as mentioned previously, arm 52 is past center and inengagement with guide rod 34, and the lamp carriage is stopped againstsliding downwardly on rods 34 and 35, with the liability of finallybreaking the light'globe.

Attention is called to the fact that the lamp carriage, guide rods, andfocusing mechanism are supported exclusively on lower housing I8, andthat this entire assembly may be removed simply by removing screws I9that secure housing I8 to frame ring flanges I3 and I4.

Fig. 6 shows a modification of the lamp carriage operating means. Theoperating'link which is connected to the lamp carriage is againindicated at 53, and the casing wall and scale plate are again indicatedby numerals 5| and 6|, respeotively. It will be understood that the lampcarriage and link 53 may be exactly the same as in the form previouslydescribed, as may the mechanism casing of which wall 5| is a part. Amanual operating shaft is journalled in wall 5| on an axis which islocated the same as is the axis of shaft 50 in the form of Fig. 4. Theexterior end of shaft 90 carries a handle 9| and a pointer 92, and itsinner end is reduced, as at 93, and is slidably received within a socket94 formed in the end of a shaft member 95. Reduced shaft end 93 has anotch 96 adapted to receive and drivingly engage a cross-pin 91 set insocket 94. Shaft member 95, which is journalled in a bearing 98 carriedby a stationary frame plate 99, is confined against longitudinalmovement by means of a flange I00 near its inner end which engages theadjacent surface of bearing 38, and a collar |0| screwthreaded onto theshaft and positioned adjacent the opposite face of said bearing.

On the extreme inner end of shaft is pinned an arm 52', exactly similarto the arm 52 of :the previously described form shown in Fig. 4, theouter end of 'arm 52' being pivotally connected to the end of link 53,as in the previous instance. It will be evident that rotation of knob 9|and shaft 90 will cause shaft 95 to be rotated to swing arm 52 for thepurpose of moving link 53 and so shifting the lamp carriage,substantially as in the previous form.

A locking device is provided to prevent accidental shifting of thefocusing mechanism as the lamp is tilted. Pinned on shaft 90 adjacentthe inner surface of wall 5| is a spur gear I06,

and normally meshing therewith is a stop element I01, which is set intowall 5|, as clearly shown in Fig. 6. It will be evident that with theparts in the position of Fig. 6, the stop element in engagement with theteeth of gear I 06 prevents shaft 90 from being rotated. But by graspingknob 9| and forcing shaft 90 inwardly until gear I03 is free of elementI01, the mechanism may be freely operated. Shaft 90 is normallyyieldingly held in the locked position of Fig. 6

by means of a coil compression spring I08 which is confined betweenflange I00 and the opposed face ofspur gear I06. Thus, tochange thefocus of the lamp, knob 9| is grasped and forced inwardly against springI08 to free gear I06 from element I01, and may then be rotated toaccomplish the desired shift of the lamp carriage. When knob 9| is thenreleased, spring I08 acts to move shaft 90 back to the position of Fig.6, gear I06 moving back into locking engagement with locking elementI01. The lamp carriage is therefore automatically locked againstmovement longitudinally on the guide rods at all times that knob 9| isnot being manually pressed inwardly to operating position, and the lampcarriage is therefore prevented during normal use of the lamp fromsliding back .and forth on its guide rods as the lamp is tilted.

Fig. '1 shows another variational form of the lamp carriage operatingmeans. In this instance the lamp carriage is shown provided on itsunderside with a'rack ;I I2, and adapted to mesh with this rack. is agear segment 3 fast on an operating shaft 4 which will be understood asjournalled for rotation in the side wall of the enclosing case. Rotationof shaft II4, which i tordisposed within the-rearward portionltherewill'be understood as, accomplished-by a manual knob of the sametypeas-illustrated in Fig. ,4, causes rotation of gear H3 to translate rackI I2 and the lamp carriage between its-proper. limits of operation. Thediameter-of gear! llis preferably such as willcause translation of thelamp carriage betweensuchflimits by a half-rotation ofshaftill.

Shaft H4 is preferably provided with a friction retarding-means the sameas is illustrated in Fig. 4, it being understood that Fig. 4 isillustrative of the friction means and operating knob used with shaft H4of Fig. 7.;Itwillbenoted, however, that shaft ill must be rotated in adirection opposite to that ofshaft 50 of Fig. 4 in order to accomplisha'given adjustment of the lamp carriage. a

, Fig. 7 also shows locking means adapted to hold the-lamp carriagesecurely in aretracted position during transportation of'the lamp. Forthis purpose, gear member I I3 is provided with a rounded, portion I20adapted tocome into engagement with anarcuate surface I at the outer end.of rack member H2 after gear ,il3 has been moved out of mesh with therack at the inner; limit of lamp carriage movement.

It will be obvious thatwhen surface-I20 is in engagement withsurface -l2l, the lamp carriage issecurely locked against translation on the.

.lustrative of and not restrictive on the broader claims appendedhereto, for variouschanges in design, structure and arrangement may bemade without, departing from the spirit and scope of said claims. a, w;Iclaim:' .I g

1. In an incandescent studio spot lamp embodyinga lampcasing having acurved-reflecof, the combination of .alight globe ,carriage within saidcasing adaptedto carry, alight globe on the axis of said reflector,.means supporting and guiding said carriage for forward and rearwardmovement ;in a direction parallel; to: the

opticalaxis of saidreflector, whereby saidlight globe is movable betweenspot and flood'positions, a manually; rotatable shaft-extending througha wall of said casing on an, axis at right angles to the direction ofcarriage movement, an

' operative interconnection between-the portion of said shaft that isinside the casing and said carriage so arranged that the light; globe ismoved between spot and full floodpositions with in one revolution of themanually rotatableshaft, and manual shaft rotating means operating onthe exterior-portion of the shaft.

2. An incandescent studio spotlamp embodying a substantially cylindriclamp casing, a. curved reflector disposed within'the rearward portionthereof, a-depending mechanism enclosing cas-t ing joined-to,said-cylindric lamp-casingat the bottom thereof, said two casingsopening into light globe is movablebetween spot and flood positions, ahorizontal manually rotatable shaft ex: tending through a side wall ofsaid depending mechanism enclosing casing and" disposed at right angles,to .the:direction of carriagemovement, an operative interconnectionbetween the portion of said shaft that is-inside the casing and-said1ca'rriageso arranged that the light globe is moved between spotand full flood positions within one revolution of. the manuallyrotatable shaft, and manual shaft rotating means operating ontheexterior portion'of the shaft. r

3, In an incandescent studio spot lampembodying a lamp casing having acurved reflector disposed within the rearward portion thereof, thecombination of a light globe carriage within said casing adapted tocarry a light globe on the axis of said reflector, means supporting andguiding said carriage for forward and rearward movement-in a directionparallel to the optical axis of said reflector, whereby said light globeis movable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing onan axis at right angles to,the direction of carriage movement, an operative. interconnectionbetween the inner portion of said shaft and thecarriage so arranged thatthe light globe is moved between spot and full flood positions withinone revolution of the, manually rotatable shaft, and friction meansyield-,- ingly resisting operation of the manual shaft. Y 4.. Anincandescent studio spot lamp ,embodying a substantially cylindri'c sidewall casing,.a curved reflector disposed within the rearward portionthereof, a depending mechanism enclosing casing joined to said side wallcasing at the bottom thereof, said two casings opening into one another,aslightglobe carriage within said cylindric casing adapted to carry alight globe on the axis ofsaid reflectonfmeans: supporting and guidingsaid carriagefor forward and rearward movement in a direction parallelto the optical axis ofsaid reflectonwhereby said light globe is movablebetwe'en'spot and flood positions, a'horizontal manually'rotatable shaftextending through a side wall of said depending mechanism enclosingcasing and disposed at right angles to the direction of carriagemovement, an

of said reflector, whereby said light globe is movablebetween spotand'flood positions, a manually rotatable shaft extending through awallof said casing on anaxisat right angles to the direction' of carriage"movement, an operative interconnection between the inner portion of theshaft and the light globe carriage, such that rotation of theshaft-through a given angle moves the carriage between spot and floodpositions, a fric-' tion disk non-rotatably mounted on said manualshaft, and a stationary friction member frictionally engaged by saidfrictiondisk.

6. In an incandescent studio spot lamp embodying a lamp casinghaving acurved reflector disposed within'the rearward portion thereof, thecombination of a light globe carriage-within'said casing adaptedv tocarry a lightglobe on the axis of said reflector, means supporting andguiding said carriage for forward and rearward movement in a directionparallel to the optical axis of said reflector, whereby said light globeis movable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothedirection of carriage movement, an operative interconnection -betweenthe inner .portion of the shaft and the light globe carriage, such thatrotation of the shaft through a given angle moves the carriage betweenspot and flood positions, a friction disk splined on said manual shaft,a coil spring member surrounding said shaft and arranged to press saidfriction disk in one direction on the shaft, and a stationary frictionmember frictionally engaged by said spring urged friction disk.

'7. In an incandescent studio spot lamp embodyinga lamp casing having acurved reflector disposed within the rearward portion thereof, thecombination of a light globe carriage within said casing adapted tocarry a light globe on the axis of said reflector, means supporting andguiding said carriage for forward and rearward movement in a directionparallel to the optical axis of said reflector, whereby said light globeis movable between spot' and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an arm on the inner portion of saidmanual shaft, and a link connected between the swinging end of said armand said carriage.

8. In an incandescent studio spot lamp embodying a lamp casing having acurved reflector disposed within. the rearward portion thereof, thecombination of a light globe carriage within said casing adapted tocarry a light globe on the axis of said reflector, means supporting andguiding said carriage for forward and rearwardmovement in a directionparallel to the optical axis of said reflector, whereby said light globeis movable between spot and flood positions, a manually rotatable shaftextending through a wall of said casing on an axis at right angles tothe direction of carriage movement, an arm on the inner portion of saidmanual shaft, a link connected between the swinging end of said arm andsaid carriage, a friction disk splined on said manual shaft, a coilspring member surrounding said shaft and arranged to press said frictionin one direction on the shaft, and a stationary friction memberfrictionally engaged by said spring urged friction disk.

9. In an incandescent studio spot lamp embodying a lamp casing having acurved reflector disposed within the rearward portion thereof, thecombination of a light globe carriage within said casing, a pair ofparallel horizontal guide rods extending parallel-to the axis of thereflector in the lower part of the lamp casing, said guide rodssupporting said light globe carriage for sliding movement therealong,such that a light globe carried by the carriage moves along the axis ofthe reflector, a horizontal manually rotatable shaft extending through awall of the casing just below and at right angles to said parallel guiderods, an operative connection between the inner portion of said shaftand the carriage so arranged that the light globe is moved between spotand full flood positions within one revolution of the manually rotatableshaft, and manual shaft rotating means operating on the exterior portionof the shaft.

10. In an incandescent studio spot lamp embodying a lamp casing having acurved reflector disposed within the rearward portionthereof, thecombination of a light globe carriage within said casing, a pair ofparallel horizontal guide rods extending parallel to-theaxis of thereflector in the lower part of the lamp casing, said guide rodssupporting said light globe carriage for sliding movement therealong,such that a light globe carried by the carriage moves along the axis ofthe reflector, a horizontal manually rotatable shaft extending throughthe casing just below and at right angles to said parallel guide rods,an arm on the inner portion of said manual shaft, a link pivotallyconnected at one end to the swinging end of said arm, and extending'fromsaid pivotal connection in a forward direction in the lamp to a forwardpivotal connection with the light globe carriage, and manual shaft.rotating means operating on the exterior portion of the shaft. 1

11. An incandescent studio spot lam'pzembody'iing a substantiallycylindric side wallic'asing, a curved reflector disposed within therearward portion thereof, a depending mechanism-enclosing casing joinedto said side wall casing at the bottom thereof, said two casings openinginto one another, a light globe carriage within said cylindric casingadapted to carry a light globe on the axisof said reflector, meanssupporting and guiding said carriage for forward and rearward movementin. a direction parallel tothev optical axis of said reflector, wherebysaid light globe is movable between spot and flood positions,

a horizontal manually rotatable sh'aft extending through a side wall ofsaid dependingmechanism enclosing casing and disposed at right angles tothe direction of carriage movement, said shaft extending exteriorly ofsaid casing and having an operating handle on its outer end, and anoperative interconnection between the inner end of said shaft and thecarriage so arranged that the light globe is moved between spot and fullflood positions within one revolution of the manually rotatable shaft.

12. In an incandescent studio spot lamp embodying a lamp casing having acurved reflector disposed within the rearward portion thereof, thecombination of a light globe carriage within said casing. a pair ofparallel horizontal guide rods extending parallel to the axis of thereflector in the lower part of the lamp casing, said guide rodssupporting said light globe carriage for said sliding movementtherealong, such that a light globe carried by the carriage moves alongthe axis of the reflector, a horizontal manually rotatableshaftextending through a wall of the casing just below and at right angles tosaid parallel guide rods, an operating arm on the inner portion of saidmanual shaft, and a link, pivotally connected at one end of the swingingend of said arm and extending from said pivotal connection in a forwarddirection in the lamp to a forward pivotal connection with the lightglobe carriage, said arm and link being so arranged as to move thecarriage from its extreme rearward to its extreme forward position by amovement of the arm from a rearwardly extended position downwardly andaround to a forwardly extended position, the swinging end of saidoperating arm being located directly below one of said guide rods,and'being engageable therewith when said arm is raised from saidrearwardly extended position to a position above horizontal to afford astop to for ward movement of the carriage.

= I .213; Inan incandescent studio spot 'lamp emibodying a lamp casinghaving a curved reflector :disposedwithin the rearward portion thereofthe whereby said light globe'is movable between spot and floodpositions; a horizontal manually rotatable shaft 'j'ournalled in saidcasing on an axis tatri'ghtzangles to the direction of carriage move-'ment,. a irotatableu'shaft journalled in line with saidmanuallyrotatableshaft, an operative connectionlbetween the last mentioned shaftand the lamp carriage, a-sliding driving connection betw'engsaid shaftssuch that the manual shaft maybe moved axialiywithout breaking'itsdriving zconnection with the other shaft, a locking member on saidmanual shaft, a stationary looking element engageable with said lockingmemberitoilockthe manual shaft against rotation in Gone .axiaLpositionof said shaft, and a' spring iyieldingly urging said manual shaft tosuch locking position, but yieldable to allow the manual shaft tobemoved axiallyto disengage'said looking member from said locking element.

14. In an incandescent studio spot lampembodyingJa lamp casing havinga'curved reflector disposed within the rearward portion thereof, theconibinationof a light globe carriage within said casing adapted tocarrya light globe'on the axis of. said reflector',tmeans supporting andguiding said carriage forforward and rearward'movement in "a directionparallel to theioptical axis of said reflector, whereby said light globeis movable between spot and flood positions, a rack on the lampcarriageextending parallel to the direction of carriage movement, a manuallyrotatable shaft extending through a wall of saidcasing on an axis atright angles to the direction of carriage movement, manual shaftrotating means j operating on the exterior portion of the shaft, and aspur gear on saidshaft meshing with said rack, saidspur gear being ofsuch size that the light globe is moved between spot and full floodpositions: within one revolution ofsaid rotatable shaft. a

15. An incandescent studio spot lamp embody ing a substantiallycylindric lamp casing, a curved reflector disposed within the rearwardportion thereof, a depending: mechanism enclosing .cas-f ing detachablymounted on thelower side of said lamp casing, said two casings openinginto one another, a light globe carriage within said cylindric lampcasing adapted to a carrya light globe on the axis of saidreflector,.means mounted on said detachable casing supporting andguiding.

said carriage for forward andrearward movement in a direction parallelto the optical axis of said reflector, whereby said light globe ismovable between spot and flood positions, .a horizontal manuallyrotatable shaft extending through a side wall of said dependingmechanism enclosing casing and disposed at right angles to the JESS c.ROSE.

